As well known, a conventional battery pack charging apparatus is constructed in such a way that the charging terminals of a battery pack come in electrical contact with the charging terminals of the battery pack charging apparatus and power is supplied from the battery pack charging apparatus to the battery pack through the charging terminals of the battery pack and the battery pack charging apparatus.
However, in such a terminal contact type battery pack charging method, the charging of the battery pack is possible only when the terminals of the battery pack and the battery pack charging apparatus come in correct electrical contact with each other, so that the use of the contact type battery pack charging apparatus is considerably inconvenient. Furthermore, the positions of the charging terminals of the battery pack and the battery pack charging apparatus must be changed according to the various designs of potable devices including potable terminals, so that a problem arises in that dedicated battery pack charging apparatuses corresponding to the locations of the charging terminals of the battery pack.
To solve the problems, a non-contact type battery pack charging apparatus using a magnetic field is provided, as disclosed in Korean Pat. Appl. No. 1999-53492 and Korean Utility Model No. 2001-27153.
However, in Korean Pat. Appl. No. 1999-53492 and Korean Utility Model No. 2001-27153, a provision for satisfactorily charging battery packs having different charge capacities for a set time is not made, so that a problem arises in that the battery pack charging apparatuses corresponding to the charge capacities must be provided.
Furthermore, even though an inductive load (conductive material) other than a capacitive load is installed on the battery pack charging apparatus, the conventional non-contact type battery pack charging apparatus regards the inductive load as a capacitive load and performs charging operations, so that a problem arises in that unnecessary power consumption is incurred.